Gastric compliance in bulimia nervosa.

Bulimia nervosa (BN) is a psychiatric illness characterized by eating binges followed by inappropriate behavioral attempts to compensate for the binges, usually vomiting or laxative abuse. Patients with BN have disturbances in the development of satiety during a meal as well as disturbances in functions of the upper gastrointestinal tract such as slowed gastric emptying, impaired gastric accommodation reflex and blunted cholecystokinin release. The present study examined gastric compliance and sensory responses to gastric distention in women with BN and controls. Sixteen women with BN and 13 healthy control subjects swallowed an inflatable bag that was placed in the proximal stomach. The bag was inflated to produce increasing steps of pressure against the stomach wall, before and after consumption of a 200 ml (200 Kcal) liquid meal. Pressure and volume were recorded for 2-min periods, beginning at 0 mm Hg pressure and increasing in steps of 2 mm Hg until subjects reported discomfort, gastric volume reached 600 ml, or pressure reached 20 mm Hg. At each pressure step subjects made sensory ratings. Gastric compliance was calculated as the slope of the best-fit straight line of each subject's gastric volume vs. gastric pressure. There was a significant postmeal increase in gastric compliance in both groups of subjects but there was no difference in compliance between patients with BN and controls. Patients with BN appeared to have diminished sensitivity to gastric distention. In conclusion, although other studies have described gastrointestinal abnormalities associated with BN, the current study found gastric compliance of patients with BN to be normal.

Microstructural analyses of human ingestive patterns: from description to mechanistic hypotheses.

Continuous automated weighing of food while subjects ate was used to test the hypothesis that failure to slow eating rate during a meal indicated a deficient response to satiety signals in obese patients. Cumulative intake curves were fitted to a quadratic equation. The physical form of the food and its palatability were a greater influence on the equation's parameters than the subjects' body weights, and the hypothesis was abandoned for several years (1984-1993). The hypothesis was revived with modifications when we discovered disturbances in eating behavior in patients with bulimia nervosa. The new hypothesis was that overeating was attributable to subjects' inability to detect or respond to satiety-related signals after eating large amounts of food. Patients with eating disorders showed lower ratings of satiety after eating the same amounts of food as controls, but only after eating more than normal. In conclusion, microstructural examination of eating behavior may be more useful for tests of specific hypotheses about the control of eating than as a description of clinical disturbance.

Patterns of food selection during binges in women with binge eating disorder.

OBJECTIVE: The aim of this study was to determine whether temporal patterns of food selection during binges in obese subjects with binge eating disorder (BED) differ from those of patients with bulimia nervosa (BN). METHOD: Ten obese women with BED and 10 weight-matched women without BED each consumed a multiple-item meal identical to that used in previous studies with bulimics, and all subjects were instructed to binge. An experimenter recorded the subjects' food choices every 10 s throughout the meal via a closed-circuit TV camera. RESULTS: Subjects with BED consumed significantly more meat than subjects without BED (397.78 vs. 270.64 kcal), but the food choices and percentages of time spent eating each of the foods were similar among BED, non-BED, and normal weight controls. While bulimics ate dessert foods earlier in the meals, all other groups ate meat towards the beginning of their meal and ate more dessert foods towards the end of the meal. DISCUSSION: Food selection patterns during binges in subjects with BED are more similar to eating patterns of noneating disordered subjects, than to patterns seen in patients with BN. These data suggest that binge episodes between different groups of eating-disordered populations are qualitatively different.

Postprandial cholecystokinin release and gastric emptying in patients with bulimia nervosa.

This study was designed to investigate the biological underpinnings of the observed deficit in satiety in patients with bulimia nervosa. Eight women with bulimia nervosa and 10 age- and weight-matched control subjects consumed three laboratory meals consisting of 200, 400, and 600 g of a radiolabeled liquid meal. For 1 h after each meal, blood samples were obtained at 10-min intervals for measurement of cholecystokinin concentration and gastric emptying was measured. Subjects also completed perceptual rating scales at 10-min intervals. Compared with control subjects, patients with bulimia nervosa showed a blunting of postprandial cholecystokinin release, particularly with larger meal sizes, as well as delayed gastric emptying. Increasing meal size was associated with increased desire to binge eat in patients but not in control subjects. These data lend support to a model in which increased gastric capacity, perhaps resulting from repeated binge eating, gives rise to delayed gastric emptying and blunted postprandial cholecystokinin release, leading to an impaired satiety response, which tends to perpetuate the illness.

A direct measure of satiety disturbance in patients with bulimia nervosa.

To determine whether patients with bulimia nervosa (BN) experience the development of satiety during a meal differently than control subjects, a novel laboratory meal procedure was employed. Eleven women with BN and 11 women without eating disorders consumed a yogurt shake meal after being instructed to binge. After each 75-g increment consumed, the subjects were signaled by a tone to fill out a questionnaire on which they were asked to rate various sensations on visual analog scales. The sensations included "Fullness", "Hunger", "Desire" for a favorite food, "Pleasantness" of consuming the shake, "Sickness", and having "Enough" to consume. Although patients, before purging, consumed significantly more food than the controls, who did not purge (1597 +/- 626.5 g vs. 1004 +/- 362.5 g, mean +/- SD), their final questionnaire ratings were not significantly different from the controls' ratings. Patients ate significantly more than the controls before reaching 50% of their range of "Hunger" rating and 75% of their "Full", "Desire", "Sick", and "Enough" rating ranges. The patients also ate significantly more than the controls between 75% and 100% of their "Hunger" rating range. These data suggest that one possible mechanism for overeating in patients with BN may be their failure to perceive or respond as normal subjects do to the range of sensations associated with satiety. Collecting ratings as a function of intake may provide a method for assessing and studying eating disturbances in clinical populations.

Subjective ratings as a function of amount consumed: a preliminary report.

A new technique has been developed to study the changes in feelings of satiety during food consumption. Five non obese women were interrupted after eating 75 g increments of a tomato soup test meal served on an eating monitor to complete rating scales of hunger, satiety, fullness, sickness, and pleasantness of the meal. They were instructed to eat as much as they could, and their intakes ranged from 590 to 1288 g. The measured responses to each question were then plotted against the corresponding intakes. The slopes of the linear portions (in mm/g on 150 mm scales) were -.22 for hunger, -.21 for pleasantness of the food, and .27 for both fullness and satiety. The slope of the relationship between satiety and intake or the difference in intake between 25% and 75% of the maximum satiety response range could be useful measures for assessing either disturbances in satiety in clinical populations, or assessing relative satiating potencies of foods or beverages.

Effects of glucose and fructose solutions on food intake and gastric emptying in nonobese women.

The differential effects of fructose and glucose on food intake were studied by giving two concentrations (1 and 10%) of glucose and fructose solutions (500 ml) to one group of women 30 min, and to another 135 min, before a meal of macaroni and beef. The 1% solutions of each sugar were sweetened to match 10% fructose by selective additions of aspartame. Gastric emptying of the 10% solutions and water was measured for 90 min. Under the 30-min delay, subjects ate a mean of 75.8 g more (P < 0.05) after the 1% solutions than after water, and 52.2 g (P > 0.05) less after the 10% solutions than after water, but there were no differences in intake between types of sugar under either delay nor between concentrations at the 135-min delay. However, 10% fructose and 1% glucose sweetened to match it reduced intake significantly compared with water. Glucose (10%) emptied significantly slower (t1/2 = 93.61 min) than water (t1/2 = 29.77 min), while fructose (10%) was intermediate (t1/2 = 65.45 min). Therefore, gastric emptying differences did not account for these results. We conclude that sweetener-enhanced dilute sugar solutions may increase subsequent intake at 30 min, but dilute glucose solutions may have potential for substantial energy savings if consumed 135 min before a meal.

Binge eating behavior in patients with eating disorders.

The purpose of this study was to determine whether the objectively observed binge eating behavior of obese subjects meeting the proposed DSM-IV criteria for binge eating disorder would be similar to that observed in patients with bulimia nervosa. Non-obese patients with bulimia nervosa (BN), obese subjects with binge eating disorder (BED), obese and non-obese women without eating disorders were each instructed to binge eat single- and multiple-item meals. In the multiple-item meal, the obese subjects with BED ate significantly more (1515 kcal) than obese subjects without BED (1115 kcal), but they ate less than the normal-weight bulimic patients (2680 kcal). The non-obese controls ate amounts similar to the obese non-binge-eating-disordered group (1093 and 1115.2 kcal, respectively). In the single-item meal, consisting of ice cream, patients with BN ate significantly more than any other group (1307 kcal), while obese subjects with or without binge-eating disorder ate significantly more (762 kcal) than non-obese controls (308 kcal). This study has demonstrated that although both BN and BED are characterized by recurrent episodes of binge eating, quantitatively there appear to be differences between the eating disturbances in the two disorders. Because single- and multiple-item meals differ in external cues, these results also suggest that the obese subjects with BED may be disinhibited by external cues, while obese subjects without BED may be inhibited by external cues.